The service, which will be held inside a 1,200-seat auditorium to accommodate the actresses legions of fans, is also being broadcast on big screens from that the cemetery and live-streamed on the internet.

Fans who have been assembling at the Hall of Liberty since 5am spoke of their affection for the famous mother-and daughter. Grace Farenbaugh from Burbank, California told PA: "I'm a huge fan of both of them. I feel they are part of my family."

Liza Rios-Proprofsky from Orange County, California, shared the sentiments of thousands of fans of Fisher, who was best known for her portrayal of Princess Leia in Star Wars.

"Star Wars has been a part of our child narrative," she said. "When Carrie Fisher passed, it actually like a member of the family had left us.

"When I was a little girl, here was this strong woman who was a princess who could take charge. We knew that if we came here we would be with people who are like minded, that would understand how we felt," she explained.

Fisher's close friend James Blunt, is expected to perform a tribute song as a photo montage captures moments from the actresses' extraordinary lives.

In a musical celebration in honour of the Singin' In The Rain star's Hollywood song and dance roots, the Gay Men's Chorus of Los Angeles will perform along with dancers from the Debbie Reynolds Dance Studio, while fans will have an opportunity to peruse costumes and memorabilia, highlighting key moments in the careers of Reynolds and Fisher.

Fisher's daughter Billie Lourd is expected to attend the public memorial along with Fisher's beloved dog Gary, Evening Standard reports.

Carrie Fisher died aged 60 on December 27 after suffering a heart attack on a flight from London to Los Angeles. A day later, her mother, Reynolds – who was 84-years-old – died following a 'severe stroke'.